Apparatuses and methods for detecting deviation of a ball from a path

ABSTRACT

Apparatuses, methods, and associated devices to detect deviation of a ball from a path when spin is applied, providing an indication about whether a spin alignment compensation is optimally calibrated for deflection of the ball. An example apparatus includes a support structure and detection members. The detection members are coupled to the support structure and arranged to allow a ball to travel between the detection members. At least one of the detection members is movable relative to the support structure and moves upon collision with the ball. The movement of at least one of the detection members indicates that the ball has deviated from a straight path of travel through the detection members. A displacement of at least one of the detection members indicates the direction of deviation of the ball, and an amplitude of movement of the detection member indicates a degree of deviation of the ball.

RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.62/362,186, filed on Jul. 14, 2016. The entire teachings of the aboveapplication are incorporated herein by reference.

BACKGROUND

While playing billiard games (e.g., carom billiards, snooker, pool,etc.), as a matter of strategy, players often desire or are required toapply sidespin (spin along the z-axis, or vertical axis) onto a cueball. This spin is commonly referred to as “English” and is referred toherein as “spin.” In order to apply spin, one must adjust one's aim inorder to strike the cue ball with a cue stick on one side or the otherof the ball's vertical center. This adjustment causes a distortedalignment from the desired path of the ball. Upon impact of the cuestick striking the cue ball off-center, both the cue stick and the cueball deflect away from each other to varying degrees, depending on therelative masses between them. The deflected ball is redirected on a paththat is at an angle, opposite to the spin being applied, to the path theball would have taken if not stuck off-center. This deflection of thecue ball is commonly referred to as “squirt.” Squirt makes it verychallenging to predict the exact path of any such billiard shot. Theexact degree of squirt is a function of physical properties of the cuestick's design, relating particularly to the cue stick's front-end massand flexibility. However, the precise degree of deflection (squirt) of acue is not a performance property that is customized, measured, orexplicitly revealed to others by cue stick manufacturers. Rather theonus is on the user of the cue to adapt the user's compensation tacticsto fit the properties of a cue through a lengthy process of trial anderror. Cue sticks have not been explicitly designed with attention onhow to make this process easier.

SUMMARY OF THE INVENTION

The disclosed apparatuses and methods detect deviation of a ball from apath, and are particularly useful when spin is applied to the ball. Oneexample apparatus is a device that includes a support structure anddetection members. The detection members are coupled to the supportstructure and arranged to allow a ball to travel between the detectionmembers. At least one of the detection members is movable relative tothe support structure and moves upon collision with the ball. Themovement of at least one of the detection members indicates that theball has deviated from a path of travel through the detection members. Adisplacement (movement) of at least one of the detection members canindicate the direction of deviation of the ball from the straight pathof travel between the detection members, and an amplitude of movement ofat least one of the detection members can indicate a degree of deviationof the ball from the straight path of travel between the detectionmembers. The distance between the detection members can be adjustable toaccommodate different size balls or the precision of deviationdetection.

In many embodiments, the detection members are rotatable about thesupport structure and rotate upon collision with the ball. In someembodiments, the rotational axes of the detection members aresubstantially vertical, and in others, the rotational axes aresubstantially horizontal. The support structure can include asubstantially horizontal cross bar, and the detection members can becoupled to the cross bar and can hang downward from the cross bar. In anembodiment, the detection members may swing freely with respect to thecross bar or may be configured to remain in a displaced position aftercolliding with the ball. Many embodiments can also include a centeralignment guide coupled to the cross bar to assist with placement of theball to travel between the detection members. In many embodiments, thedeviation of the ball is caused by an implement striking the ball topropel the ball and to induce spin on the ball. In an embodiment, aguide may be used to assist the implement in striking the ball from aconsistent angle. An example of a ball and implement to be used with thedisclosed devices are a cue ball and cue stick.

Another example apparatus is a device that includes a support structureand sensors. The sensors can be coupled to the support structure andarranged to allow a ball to travel between the sensors. The sensors arearranged to detect deviation of the ball from a path of travel throughthe sensors. The sensors may include, for example, lasers or opticalsensors, such as photo sensors, and the distance between the sensors canbe adjustable. In many embodiments, the support structure can include asubstantially horizontal cross bar, and the sensors may be coupled tothe cross bar and aimed downward from the cross bar. Triggering of oneof the sensors can indicate the direction of deviation of the ball fromthe path of travel between the sensors, and the sensors may measure adegree of deviation of the ball from the straight path of travel betweenthe sensors.

An example method of detecting deviation of a ball from a path includesarranging a camera to capture video of the ball placed on a surface. Theball is struck with an implement to propel the ball along a desired pathon the surface. Video of the ball is captured including when and afterthe ball is struck by the implement, and frames of the video areanalyzed to determine whether the ball, when struck by the implement,deviation from the desired path. The method then reports whether theball deviated from the desired path. Analysis of the video frames mayoccur in real-time, and a direction or degree of deviation can bereported. An angle at which the implement struck the ball may also bedetermined and it can be reported whether the angle adequatelycompensated for deflection of the ball.

Another example method of detecting deviation of a ball from a pathincludes arranging a camera to capture video of a cue ball placed on asurface. The ball is struck with a cue stick to propel the ball alongthe surface and to induce spin on the ball. Video of the ball, path, andcue stick alignment is captured including when and after the ball isstruck by the cue stick, and frames of the video are analyzed todetermine how, and to what degree, the ball, when struck by the cuestick, was deflected by the cue stick. The method then reports both theangle of the cue stick and the angle of the ball path as it wasdeflected. The degree of compensation error can also be reported.

An example device for guiding a cue stick includes an apparatus that caninclude a bridge, a rail, and a slidable shuttle coupled to the rail.The bridge supports a fore end of the cue stick, and the slidableshuttle supports the cue stick at a point rearward of the fore end,where the cue stick is pivotable at the point of contact with theshuttle.

An example method of quantifying characteristics of a cue stick includesdetermining a balance point of the cue stick, determining a pivot pointof the cue stick based on deflection characteristics of the cue stick,and assigning a value to the cue stick that quantifies a relationshipbetween the balance point and the pivot point of the cue stick. Usingthe method of quantifying characteristics, a system of assigning valuesto cue sticks provides standardized cue sticks for selection andpersonalization of the cue sticks for their use in play.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing will be apparent from the following more particulardescription of example embodiments of the invention, as illustrated inthe accompanying drawings in which like reference characters refer tothe same parts throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingembodiments of the present invention.

FIG. 1A is a schematic drawing of a device for detecting deviation of aball from a path, according to an example embodiment of the invention.

FIGS. 1B-D are schematic diagrams illustrating how the example device ofFIG. 1A can be used to detect deviation of a ball from a path and tocalibrate compensation for deflection.

FIGS. 2A and 2B are schematic drawings illustrating how an exampledevice can be used to detect deviation of a ball from a path and tocalibrate compensation for deflection.

FIG. 2C illustrates quantifying characteristics of a cue stick.

FIG. 3 is a schematic drawing of a device for detecting deviation of aball from a path, according to an example embodiment of the invention.

FIG. 4A is a schematic drawing of a device for detecting deviation of aball from a path, according to an example embodiment of the invention.

FIG. 4B is a schematic drawing of a device for detecting deviation of aball from a path, according to an example embodiment of the invention.

FIG. 5A is a schematic drawing of a device for detecting deviation of aball from a path, according to an example embodiment of the invention.

FIG. 5B is a schematic drawing of a device for detecting deviation of aball from a path, according to an example embodiment of the invention.

FIG. 6 is a schematic drawing of a device for detecting deviation of aball from a path, according to an example embodiment of the invention.

FIG. 7A is a flow chart illustrating a method for detecting deviation ofa ball from a path, according to an example embodiment of the invention.

FIG. 7B is a flow chart illustrating a method for detecting deviation ofa ball from a path, according to an example embodiment of the invention.

FIGS. 8A-D are photographs of an example device for detecting deviationof a ball from a path, according to an example embodiment of theinvention.

FIG. 9 is a schematic drawing of a device for detecting deviation of aball from a path, according to an example embodiment of the invention.

FIG. 10 is a schematic drawing illustrating a cue stick being used tolift and move the device of FIG. 9.

FIG. 11 is a schematic drawing of a device for detecting deviation of aball from a path, according to an example embodiment of the invention.

FIG. 12 is a schematic drawing of a device for detecting deviation of aball from a path, according to an example embodiment of the invention.

FIG. 13 is a schematic drawing of a device for detecting deviation of aball from a path, according to an example embodiment of the invention.

FIGS. 14A-D are photographs of an example device for detecting deviationof a ball from a path, according to an example embodiment of theinvention.

FIG. 15 is a schematic drawing of a device for detecting deviation of aball from a path, according to an example embodiment of the invention.

FIG. 16 is a schematic drawing of a device for detecting deviation of aball from a path, according to an example embodiment of the invention.

FIG. 17 is a schematic drawing illustrating how an example device can beused to detect deviation of a ball from a path and to calibratecompensation for deflection.

DETAILED DESCRIPTION OF THE INVENTION

A description of example embodiments of the invention follows.

As described above, when a cue stick impacts a cue ball off-center to,for example, induce spin on the ball, the cue stick, due to itsdifferent mass relative to the mass of the ball, displaces the ball atan angle directed away from the spin being applied. This redirection ofthe ball line away from the cue stick aiming line is referred to as adeflection of the cue ball, also known as “squirt.” The deflection (orsquirt) makes it challenging to predict the exact path of the ball. Tocomplicate matters further, a spinning ball interacts with the table bedcausing it to curve slightly back toward the original aiming line—aneffect that reduces, or cancels, part of the original squirt. Unless thecue stick is significantly elevated, this “swerve” effect is barelynoticeable over short distances and even less noticeable at fasterspeeds. It should be noted that the phenomena of cue ball swerve isrelated to the frictional properties of the ball and table and notdirectly linked to the properties of the cue stick. While practitionersmust contend with the combined distortions of squirt and swerve(sometimes called “squerve”) when compensating for spin shots, it isimportant to be able to measure the extent that each distortioncontributes individually in order to understand the overall processwell.

The precise angle of adjustment required to make spin shots accuratelydepends considerably on the physical properties of the cue stick beingused to strike the cue ball. There is a wide range of cue sticksavailable, each with varying degrees of end mass and flexibility, themain factors that affect deflection. Billiard cue stick manufacturershave historically prescribed a one-size-fits-all model to custom cuestick design with respect to deflection performance. There is aprevailing notion in some parts of the industry that the effects ofsquirt must necessarily be reduced to the point of elimination(zero-deflection)—a concept that is not physically realistic. Thedevices and methods described herein make it possible to quantifydeflection, which can lead to a standardization and tailoring ofdeflection performance metrics in the cue stick manufacturing industry.Furthermore, the concepts and methods described herein demonstrate thatthe reduction of deflection is not necessarily optimal for certainindividuals—depending on their form factor. For example, individuals ofshort stature (with shorter “wingspan”) actually require higherdeflection performance, while players with longer arms require lowerdeflection cues, in order to optimize their ability to compensateconsistently.

Choosing an appropriate aiming alignment for each shot represents amajor challenge for practitioners, and developing the ability toaccomplish aiming alignment consistently and successfully usually has anextended learning curve because the mechanics of squirt (cue balldeflection) happen too quickly for the eye to see, making it difficultto gauge both the direction and degree of the squirt properly. Players,if they notice the effect at all, tend to incorrectly judge properly thenature of deflection such that they can consistently make a consciousand appropriate correction. The devices and methods described hereinprovide the observer with immediate feedback about spin alignment errorsduring practice, which allows for much higher quality training andsuccessful development of a working sidespin compensation strategy.

FIG. 1A is a schematic drawing of a device 100 for detecting deviationof a ball 105 from a path, according to an example embodiment of theinvention. The device 100 includes a support structure 110 and detectionmembers 115 a,b. The detection members 115 a,b are coupled to thesupport structure 110 and arranged to allow the ball 105 to travelbetween the detection members 115 a,b. The detection members 115 a,b aremovable relative to the support structure 110 and move upon collisionwith the ball 105. In the embodiment of FIG. 1A, the support structure110 includes a substantially horizontal cross bar. In the exampleembodiment shown, the detection members 115 a,b are coupled to the crossbar, hang downward from the cross bar, are rotatable about the crossbar, and rotate upon collision with the ball. The distance between thedetection members can be adjusted. An example use of the device 100 ofFIG. 1A is to analyze a billiard shot, in which case the ball 105 is acue ball that is struck by a cue stick, that can induce spin on the ball105. To use the device 100, a user places the ball 105 between the userand the device 100, strikes the ball 105 with an implement to, forexample, induce spin on the ball and to propel the ball through thedevice 100. If the user has not adequately compensated for deflection ofthe ball 105 when the ball is struck off-center, then the ball 105 willcollide with one of the detection members 115 a and 115 b. A user maytypically place the ball 105 about one inch in front of the device 100,but can place the ball at any distance. Greater distances provide a morechallenging use of the device because the ball 105 would have more of anopportunity to deviate from a desired path through the device before theball 105 reaches the device 100.

In the case of FIG. 1A, the detection members 115 a,b swing freelyback-and-forth (in and out of the page, from the perspective shown inFIG. 1A), though in other embodiments the detection members 115 a,b mayremain displaced after collision with the ball 105 by, for example,using a ratcheting mechanism. The movement of at least one of thedetection members 115 a,b indicates that the ball 105 has deviated froma path of travel through the detection members 115 a,b. If, for example,detection member 115 b is displaced after the ball 105 is propelledthrough the detection members 115 a,b, the displacement of detectionmember 115 b indicates that the direction of deviation of the ball 105from the path of travel between the detection members 115 a,b was to theright, toward detection member 115 b. The amplitude of movement of thedisplaced detection member indicates a degree of deviation of the ball105 from the path of travel between the detection members 115 a,b. Forexample, if the ball 105 deviates only slightly to the right, theamplitude of movement of detection member 115 b may only be slightbecause the ball 105 may only slightly nudge detection member 115 b. Onthe other hand, if the degree of deviation is great, a substantialportion of the ball may impact detection member 115 b and, thus,increase the amplitude of displacement of detection member 115 b.

FIGS. 1B-D are schematic diagrams illustrating how the example device ofFIG. 1A can be used to detect deviation of a ball from a path and tocalibrate compensation for deflection. FIG. 1B shows how a user of thedevice 100 can position the ball 105 in front of the device at anarbitrary distance Y. The arbitrary distance may be about one inch, forexample, but can be any distance depending on the preference of theuser. FIG. 1B also illustrates a “handle” 120 that may be included atthe middle of the device 100. The handle 120 can be used to position andalign the device and as a visual alignment tool for ball placement.

FIG. 1C illustrates, from a top view, the ball 105 being struck by animplement 125 to induce spin on the ball. As shown in FIG. 1C, the userof the implement 125 has not compensated for deflection (squirt) of theball. FIG. 1D illustrates, from a top view, the ball 105 being struck byan implement 125 to induce spin on the ball. As shown in FIG. 1D, theuser of the implement 125 has compensated for deflection (squirt) of theball by pivoting the implement 125 about a pivot point 130.

FIGS. 2A and 2B are schematic drawings illustrating how an exampledevice (e.g., the device 100 of FIG. 1A) can be used to detect deviationof a ball from a path and to calibrate compensation for deflection. FIG.2B also shows an example bridge 230, mechanical rail 235, and slidingshuttle 240 that can be used alone or in combination as an apparatus toinsure that a straight stroke of a cue stick is made.

FIG. 2A illustrates four aiming scenarios 200 a-d. In each scenario, thedashed line 210 a-d is a desired straight path of a ball 205 a-d. Thesolid line 215 a-d is the line of a cue stick, which necessarily must beangled away from the deflection effect at X degrees, which is ananticipated deflection. The dotted lines 220 a-d are the paths of thecue ball 205 a-d. The cue stick pivot points (target symbols) 225 b-dshow how manipulating the pivot point of a cue stick adjusts the angleof compensation. The four scenarios 200 a-d illustrate how pivot pointrelates to a compensation strategy and leads to an understanding of anoptimal cue stick for a particular person (giving rise to a “sizing”property of each cue stick). Each cue stick deflects a cue balldifferently (according to the mass of the cue stick's front end) and atan angle that is proportional to the tip offset applied during spin. Auser can practice moving the user's hands laterally to learn how muchthe user must angle the user's cue when compensating for shots withspin.

With this concept in mind, a correct “size” cue stick for a user can bedetermined. Users angle their cue sticks in order to compensate forspin. This compensation is best made by basing their stick line on thesame line as their desired cue ball path (dashed line) 210 a-d. Fromthis line, a user must move the user's bridge hand to point the tip tothe cueing spot (on the cue ball) for the desired spin. This strategy(called Front-Hand-English or FHE) creates an angle, which depends onthe tip offset and the pivot point of the user's back hand. If the anglecreated by moving the user's front hand matches the natural squirt angleof the cue stick, then the cue ball will follow the desired path (dashedline) 210 a-d. Otherwise, the user must move the user's back hand aswell to achieve the correct compensation angle. Any cue stick thatrequires a user to move both hands can be considered less optimalbecause a compensation strategy of angling the cue will be a lessrepeatable task. Thus, a cue stick held at a pivot point that naturallycreates the proper compensation angle that matches the deflection of thecue stick is optimal. The right match for a user allows the user to holdand stroke the cue at this pivot point, thus allowing the user to applyEnglish by only moving the user's front (bridge) hand. The cue stickindustry does not match cue stick deflection properties to a balancedlocation where individual users prefer to hold their cue sticks. Theabove concept enables a cue stick to be measured, standardized with anumbering type of system, and provided with an indication on the cuestick, which could be an indicator strip, for example, positioned at anoptimal pivot point or range that naturally compensates for thedeflection with FHE and allows for personalized use of the cue stickbased on the location of the indication. The user of a cue stick canthen obtain a cue and, via the indicator, test whether the optimal pivotpoint for deflection compensation coincides with where the cue stickfeels most balanced for the user. Cue sticks may also be provided withnumbers that allow a user to select a cue according to where the userprefers to hold the cue (where it feels balanced), rather than adjustthe user's pose or posture around the fixed properties of a given cuestick, particularly a cue stick that is not standardized or that doesnot allow for personalized use.

Because of this, it is possible to construct (or measure and label) acue with specific properties that enable a simple and reliablecompensation strategy to be applied while simultaneously matching thecue to a particular user given the varying sizes and forms of the widerange of users. A tailor-fit, balanced back-hand grip position,specifically designed to coincide with an optimal pivot point or rangeof the cue, that geometrically compensates for the natural squirt anglecan be determined. A cue that satisfies these conditions can allow auser to more easily compensate for spin. Precise tools may be used totest and measure the effects and performance of cues, as described inconjunction with FIG. 2B. Also, an example set of functional parametersto reliably quantify the deflection performance and balance of cues isdescribed in conjunction with FIG. 2C.

FIG. 2B shows an example bridge 230, mechanical rail 235, and slidingshuttle 240 that can be used to insure that a straight stroke of a cuestick is made. Such a device can be used when testing cue sticks fordeflection performance, as described above. The mechanical rail 235 andsliding shuttle 240 can also be used with a bridge piece 230. As withFIG. 2A, the dashed lines 210 e,f are a desired path of a ball, thesolid lines 215 e,f are the lines of a cue stick, the dotted lines 220e,f are the paths of the cue ball, and the cue stick pivot points(target symbols) 225 e,f show how manipulating the pivot point of thecue stick adjusts the angle of compensation. The sliding shuttle 240 canbe moved along the mechanical rail 235 to adjust the cue stick pivotpoint.

FIG. 2C illustrates an example “Standard Cuestick DeflectionSpecification” (SCDS) that can be used to quantify the deflectionperformance and balance of cues, according to an example embodiment ofthe invention. The typical pivot point for a billiard cue necessitatesthe movement of both hands to compensate for deflection due to the factthat the effect of squirt is very high with existing cue designs.According to the principles of the disclosed embodiments, compensatingfor squirt is much easier if a cue has a pivot point behind its balancepoint (where a user may prefer to grip the cue), thus enabling the userto move only the user's fore (bridge) hand. The following describes howthe pivot and balance properties of a cue can be quantified.

An example cue stick specification format is <scale> p [+|−] b, where pis the pivot distance from tip in centimeters, and b the offset ofbalance point to grip hand in centimeters. See cue stick 250 in FIG. 2Cfor example cue stick measurements. The <scale> may be selected from C,P, and S, where C refers to Carom (61.5 mm diameter ball, 209 g), Prefers to Pool (57.15 mm diameter ball, 156-170 g), and S refers toSnooker (52.5 mm diameter ball). As an example, a sample specificationis “C120-10” where C refers to Carom, 120 is the pivot distance, and −10is the balance point offset.

After measuring the cue ball squirt characteristics of a particular cuestick, a specification for a cue stick can be designed that informs auser about the location of the stick's natural pivot point. The degreeof cue ball squirt depends on the type of billiards to be played (e.g.,Carom, Pool, Snooker) because the mass and size of the balls used in thedifferent games changes the deflection angle experienced. A “C”, P”, or“S” specification prefix indicates this scale. With the squirt anglemeasured using the maximum tip offset for a given sized ball (RISE), anoptimal pivot distance can be determined by using a table that gives thetrigonometric relationship among cueing angle, tip offset (RISE), andthe grip hand distance (RUN). An example of such a table 255 is shown inFIG. 2C. If the specification has a low pivot value (e.g., within theshaft of the stick), then a Back Hand English (BHE) strategy is calledfor. If the specification has a high pivot value (e.g., on the buttbehind the balance point), then a Fore Hand English (FHE) strategy iscalled for. If the specification has a pivot value that sits between thebridge hand and the grip hand, then a combination BHE/FHE strategy wouldbe required. The relationship of the grip hand to the balance point isspecified via a relative offset to the pivot point. If the balance pointsits behind the pivot point, then the balance point offset is positive.If the balance point sits in front of the pivot point, then the balancepoint offset is negative. The above sample specification “C120-10”denotes a carom cue with the optimal pivot point (grip) that is 120 cm(1200 mm) from the tip of the cue and 10 cm (100 mm) behind the balancepoint.

According to the above method, cue stick 260 has a SCDS of C60+41,meaning that for a Carom scale, cue stick 260 has a pivot length of 60centimeters and a balance point 41 centimeters behind the pivot point.As described above, cue stick 260 has a pivot value that sits between auser's bridge hand and grip hand and, thus, a combination BHE/FHEstrategy is required. This configuration is not optimal as using bothhands to predictably create angle settings is difficult to reproduceconsistently.

According to the above method, cue stick 265 has a SCDS of C120-10,meaning that for a Carom scale, cue stick 265 has a pivot length of 120centimeters and a balance point 10 centimeters in front of the pivotpoint. As described above, cue stick 265 has a pivot point that isbehind the balance point, which is desirable for applying FHE.

FIG. 3 is a schematic drawing of a device 300 for detecting deviation ofa ball 305 from a path, according to an example embodiment of theinvention. The device 300 is similar to that of FIG. 1A and includes asupport structure 310 and detection members 315 a,b. The detectionmembers 315 a,b are coupled to the support structure 310 and arranged toallow the ball 305 to travel between the detection members 315 a,b. Thedetection members 315 a,b are movable relative to the support structure310 and move upon collision with the ball 305. The device 300 of FIG. 3also includes a center alignment guide 320 coupled to the cross bar ofthe support structure 310 to assist with placement of the ball 305. Suchan alignment guide is not limited to the device 300 of FIG. 3, and canbe included in any embodiment.

FIG. 4A is a schematic drawing of a device 400 for detecting deviationof a ball 405 from a path, according to an example embodiment of theinvention. The device 400 includes a support structure 410 and detectionmembers 415 a,b. The detection members 415 a,b are coupled to thesupport structure 410 and arranged to allow the ball 405 to travelbetween the detection members 415 a,b. The detection members 415 a,b aremovable relative to the support structure 410 and move upon collisionwith the ball 405. In the embodiment of FIG. 4A, the detection members415 a,b are arranged to rotate about the support structure aboutsubstantially vertical axes. The movement of at least one of thedetection members 415 a,b indicates that the ball 405 has deviated froma path of travel through the detection members 415 a,b. If, for example,detection member 415 a is displaced after the ball 405 is propelledthrough the detection members 415 a,b, the displacement of detectionmember 415 a indicates that the direction of deviation of the ball 405from the path of travel between the detection members 415 a,b was to theleft, toward detection member 415 a. FIG. 4A shows the detection members415 a,b as having a straight vertical edge, but the detection members415 a,b may also have other shapes, such as a curved shape as shown inthe embodiments of FIGS. 4A and 11.

FIG. 4B is a schematic drawing of a device 450 for detecting deviationof a ball 405 from a path, according to an example embodiment of theinvention. The device 450 includes a support structure 460 and detectionmembers 465 a,b. The detection members 465 a,b are coupled to thesupport structure 460 and arranged to allow the ball 405 to travelbetween the detection members 465 a,b. The detection members 465 a,b aremovable relative to the support structure 460 and move upon collisionwith the ball 405. Similar to the device 400 of FIG. 4A, the detectionmembers 465 a,b are arranged to rotate about the support structure aboutsubstantially vertical axes. Movement of at least one of the detectionmembers 465 a,b indicates that the ball 405 has deviated from a path oftravel through the detection members 465 a,b. The detection members 465a,b of device 450 are shaped to substantially conform to the shape ofthe ball 405.

FIG. 5A is a schematic drawing of a device 500 for detecting deviationof a ball 505 from a path, according to an example embodiment of theinvention. The device 500 includes a support structure 510 and sensors515 a,b. The sensors 515 a,b are coupled to the support structure 510and arranged to allow the ball 505 to travel between the sensors 515a,b. The sensors 515 a,b detect deviation of the ball 505 from a path oftravel through the sensors 515 a,b. The sensors 515 a,b may include, forexample, lasers or optical sensors, such as photo sensors, and thedistance between the sensors may be adjusted. The example device 500 ofFIG. 5A includes a substantially horizontal cross bar as part of thesupport structure 510. The sensors 515 a,b are coupled to the cross barand are aimed downward from the cross bar. If the ball 505 is deflectedenough to trigger one of the sensors 515 a,b, then the triggered sensorcan indicate (e.g., by itself or through a display device) to anobserver which direction the ball 505 deviated. The display device canbe, for example, an audio or visual display device. The sensors 515 a,bcan also be configured to measure a degree of deviation of the ball 505from the path of travel between the sensors 515 a,b. One example way ofdetermining a degree of deviation is to use multiple sensors on eachside of the path of travel of the ball 505 through the device. Forexample, sensor 515 b can include a plurality of sensors placed alongthe cross bar. If the deviation of the ball 505 is slight, the ball 505may only trigger one (e.g., the inner-most sensor) of the plurality ofsensors, but if the degree of deviation is great, the ball 505 maytrigger multiple sensors. In addition to the sensors 515 a,b, visualguides may be added to provide a user with visual representations of thedetection member positions. Such visual guides can be, for example, thinbarriers that hang down from the cross bar or that extend inward fromthe vertical portions of the support structure. Such visual guides canalso provide additional feedback to the user by moving if the ballcollides with them.

FIG. 5B is a schematic drawing of a device 550 for detecting deviationof a ball 505 from a path, according to an example embodiment of theinvention. The device 550 includes a support structure 560 and sensors565 a,b. The sensors 565 a,b are coupled to the support structure 560and arranged to allow the ball 505 to travel between the sensors 565a,b. The sensors 565 a,b detect deviation of the ball 505 from a path oftravel through the sensors 565 a,b. Similar to the device 500 of FIG.5A, the sensors 565 a,b may include, for example, lasers or opticalsensors. The example device 550 includes a substantially horizontalcross bar as part of the support structure 560, and the sensors 565 a,bare coupled to the cross bar and aimed downward from the cross bar. Thedevice 550 also includes detection members 570 a,b (left and rightflaps) that are shaped to allow a user of the device 550 to visualize aspace between the detection members 570 a,b that form a “ghost balltarget.” The detection members 570 a,b are configured to move when theball 505 collides with either of the detection members 570 a or 570 b.

FIG. 6 is a schematic drawing of a device 600 for detecting deviation ofa ball 605 from a path, according to an example embodiment of theinvention. The device 600 includes a camera 610 arranged to capturevideo of the ball 605. When the ball 605 is struck with an implement 625(e.g., cue stick) to propel the ball 605 along a surface and perhaps toinduce spin on the ball 605, the camera 605 captures video of the ball605. A processor 615 in communication with the camera 610 analyzesframes of the video to determine whether the ball 605, when struck bythe implement 625, deviated from a desired path. A display device 620,such as a monitor, in communication with the processor 615 reportswhether the ball 605 deviated from the path. The processor 615 cananalyze the frames of the video in real-time, and can report via thedisplay device 620 a direction and degree of deviation of the ball 605.The embodiment of FIG. 6, as well as any other embodiment, can be usedwith a guide 630 to assist the implement 625 in striking the ball 605from a consistent angle. Further or other embodiments can use a linearactuator to cause the implement 625 to strike the ball 605. Use of sucha linear actuator can help strike the ball 605 with a consistent force,which can be useful for testing purposes (e.g., testing for deflectioncharacteristics of the implement 625).

FIG. 7A is a flow chart illustrating a method 700 of detecting deviationof a ball from a path, according to an example embodiment of theinvention. According to the example method 700, a camera is arranged(705) to capture video of the ball placed on a surface. The ball isstruck (710) with an implement to propel the ball along a desired pathon the surface. Video of the ball is captured (715) while and after theball is struck by the implement, and frames of the video are analyzed(720) to determine whether the ball, when struck by the implement,deviated from the desired path. The method then reports (725) whetherthe ball deviated from the desired path.

FIG. 7B is a flow chart illustrating a method 750 of detecting deviationof a ball from a path, according to an example embodiment of theinvention. According to the example method 750, a camera is arranged(755) to capture video of the ball placed on a surface. The ball isstruck (760) at a compensated angle with an implement to propel the ballalong a desired path on the surface while inducing spin on the ball.Video of the ball, implement, and desired path is captured (765)including while and after the ball is struck by the implement, andframes of the video are analyzed (770) to determine deflection of theball when struck by the implement, and to determine whether thecompensation angle appropriately compensated for the deflection. Themethod then reports (775) whether the compensation angle appropriatelycompensated, under compensated, or over compensated for the defection.

FIGS. 8A-D are photographs of an example device for detecting deviationof a ball (e.g., cue ball) from a path, according to an exampleembodiment of the invention. The example embodiment shown in FIGS. 8A-Dis a gate-like device that includes a center alignment guide and anadjustable-width opening allowing for a ball to pass through. Theopening can be adjusted to be more or less challenging. According to theexample embodiment, two thin, lightweight, and freely-swinging detectionmembers, hinged from a supporting bar above, one to the left and one tothe right of the opening, serve as indicators that provide visualfeedback telling a user if he has overcompensated, undercompensated, orcorrectly compensated for cue ball squirt. When the alignment orcompensation is incorrect, the ball will collide with one of thedetection members, causing it to swing on its hinges as the ball passesthrough. Depending on which English (left or right) was applied to theball, the disturbance of a detection member indicates the nature anddegree of stroking alignment issues or if the user has overcompensatedor undercompensated for squirt. In general, if the user hasunder-compensated, the detection member opposite to the spin beingapplied is triggered, and if the user has over-compensated, thedetection member on the same side as the spin being applied istriggered. The strength of the collision is an indication as to thedegree of compensation error.

FIG. 9 is a schematic drawing of a device 900 for detecting deviation ofa ball from a path, according to an example embodiment of the invention.The device 900 includes a support structure 910 and detection members915 a,b. The detection members 915 a,b are coupled to the supportstructure 910 and arranged to allow a ball to travel between thedetection members 915 a,b. The detection members 915 a,b are movablerelative to the support structure 910 and move upon collision with aball. In the embodiment of FIG. 9, the detection members 915 a,b eachincludes a support bar with a hanging component to contact a ball. Whena ball collides with a hanging component, the ball causes the hangingcomponent to vibrate. The detection members 915 a,b are in communicationwith respective accelerometers 920 a,b, which process vibration of thedetection members 915 a,b to determine an amplitude of vibration of thedetection members 915 a,b. The amplitude of movement is reported to auser of the device 900 via respective LED indicators 925 a,b. Accordingto the embodiment of FIG. 9, separate crossbars are used to isolatevibration signals of the respective detection members 915 a,b. Thebridge of the support structure 910 may be made of a vibration dampeningmaterial to further isolate signals between the accelerometers 920 a,b.The LED display indicators 925 a or 925 b (e.g., in the form of digitsor bars) indicate how severe the ball's contact was with a correspondingdetection member 915 a or 915 b. For example, zero LEDs (or the number“0”) can indicate no contact, while nine LEDs (or the number “9”) canindicate hard contact. Bluetooth, or other wireless communications, canbe used to transmit accelerometer readings to a mobile device (e.g.,iPhone, iPad, or computer).

FIG. 10 is a schematic drawing illustrating a cue stick 1005 being usedto lift and move the device 900 of FIG. 9. As shown in FIG. 10, a“handle” 930 may be included at the “voussoir” position in an archway(or middle of a crossbar) of the device 900. The handle 930 can be usedto easily position the device into centered alignment and ready-to-use.The handle 930 may be a triangle-shaped tab, for example, with achannel, substantially perpendicular to the front plane of the device900, passing through the handle 930. The channel is intended to bein-line with a user's cue 1005 to enable the user to move and correctlyalign the device 900 using the fore end of a cue. Thus, the handle 930can serve as a visual alignment tool for ball placement (centered in thearchway and between the clear span of the device 900) or, as describedabove, as a handle with which a user may pick up and reposition thedevice 900 using the front of the cue stick 1005, for example. Such ahandle is not limited to the embodiment of FIG. 9, and can be includedin any other embodiment.

FIG. 11 is a schematic drawing of a device 1100 for detecting deviationof a ball from a path, according to an example embodiment of theinvention. Device 1100 is similar to device 900, but the detectionmembers 1115 a,b include thin plastic flaps connected to electronicaccelerometers (not shown) and LED indicators 1125 a,b.

FIG. 12 is a schematic drawing of a device 1200 for detecting deviationof a ball from a path, according to an example embodiment of theinvention. Device 1200 is similar to device 900, but the detectionmembers 1215 a,b include hanging spindles 1215 a,b. The spindleconfiguration in FIG. 12 can be configured to optimize visual feedback.

FIG. 13 is a schematic drawing of a device 1300 for detecting deviationof a ball 1305 from a path, according to an example embodiment of theinvention. Device 1300 includes a support structure 1310 and detectionmembers 1315 a,b. The detection members 1315 a,b are coupled to thesupport structure 1310 and arranged to allow the ball 1305 to travelbetween the detection members 1315 a,b. The detection members 1315 a,bare movable relative to the support structure 1310 and move uponcollision with the ball 1305. In the embodiment of FIG. 13, the supportstructure 1310 includes a substantially horizontal cross bar. In theexample embodiment shown, the detection members 1315 a,b are coupled tothe cross bar, hang downward from the cross bar, and move upon collisionwith the ball 1305. The detection members 1315 a,b are shaped to allow auser of the device 1300 to visualize a ghost ball target. The device1300 also includes a center alignment guide 1320 coupled to the crossbar of the support structure 1310 to assist with placement of the ball1305.

FIGS. 14A-D are photographs of an example device for detecting deviationof a ball (e.g., cue ball) from a path, according to an exampleembodiment of the invention. The example embodiment shown in FIGS. 14A-Dis a gate-like device that includes a center alignment channel and anopening allowing for a ball to pass through. According to the exampleembodiment, two thin, lightweight detection members, coupled to asupport structure, one to the left and one to the right of the opening,serve as indicators that provide visual feedback telling a user if hehas overcompensated, undercompensated, or correctly compensated for cueball squirt. When the alignment or compensation is incorrect, the ballwill collide with one of the detection members, causing it to swing onits hinges as the ball passes through. Depending on which English (leftor right) was applied to the ball, the disturbance of a detection memberindicates the nature and degree of stroking alignment issues or if theuser has overcompensated or undercompensated for squirt. In general, ifthe user has under-compensated, the detection member opposite to thespin being applied is triggered, and if the user has over-compensated,the detection member on the same side as the spin being applied istriggered. The strength of the collision is an indication as to thedegree of compensation error. FIG. 14 D shows a user using the channellocated at the center of the support structure to move and align thedevice using the fore end of a cue stick.

FIG. 15 is a schematic drawing of a device 1500 for detecting deviationof a ball 1505 from a path, according to an example embodiment of theinvention. The device 1500 includes a support structure 1510 anddetection members 1515 a-d. The detection members 1515 a-d are coupledto the support structure 1510 and arranged to allow the ball 1505 totravel between the detection members 1515 a-d. The detection members1515 a-d are movable relative to the support structure 1510 and moveupon collision with the ball 1505. In the embodiment of FIG. 15, thedetection members 1515 a-d are arranged to rotate about the supportstructure about substantially vertical axes. The movement of at leastone of the detection members 1515 a-d indicates that the ball 1505 hasdeviated from a path of travel through the detection members 1515 a-d.The device 1500 includes multiple layers of detection members. Thefirst, foremost layer includes detection members 1515 a and 1515. Asecond layer, behind the first layer, includes detection members 1515 cand 1515 d. The device 1500 can include any arbitrary number of suchlayers. FIG. 15 shows the detection members 1515 a-d as having astraight vertical edge, but the detection members 1515 a-d may also haveother shapes, such as a curved shape as shown in the embodiments of FIG.16. Further, the detection members 1515 a-d, instead of being configuredto rotate about substantially vertical axes, may be configured to rotateabout substantially horizontal axes.

FIG. 16 is a schematic drawing of a device 1600 for detecting deviationof a ball from a path, according to an example embodiment of theinvention. The device 1600 includes a support structure 1610 anddetection members 1615 a-d. The detection members 1615 a-d are coupledto the support structure 1610 and arranged to allow the ball to travelbetween the detection members 1615 a-d. The detection members 1615 a-dare movable relative to the support structure 1610 and move uponcollision with the ball. Similar to the device 1500 of FIG. 15, thedetection members 1615 a-d are arranged to rotate about the supportstructure about substantially vertical axes. Movement of at least one ofthe detection members 1615 a-d indicates that the ball has deviated froma path of travel through the detection members 1615 a-d. The device 1600includes multiple layers of detection members. The first, foremost layerincludes detection members 1615 a and 1615. A second layer, behind thefirst layer, includes detection members 1615 c and 1615 d. The device1600 can include any arbitrary number of such layers. The detectionmembers 1615 a-d of device 1600 are shaped to substantially conform tothe shape of the ball. The detection members 1615 a-d, instead of beingconfigured to rotate about substantially vertical axes, may beconfigured to rotate about substantially horizontal axes.

FIG. 17 is a schematic drawing illustrating how an example device (suchas, for example, device 1500 or 1600 of FIGS. 15 and 16) can be used todetect deviation of a ball from a path. FIG. 17 illustrates a top viewof an example device including multiple layers of detection members, inthis case two layers. The first, foremost layer includes detectionmembers 1715 a and 1715 b. A second layer, behind the first layer,includes detection members 1715 c and 1715 d. Such a device withmultiple layers can provide more information regarding alignment and thedirection of deviation of a ball 1705. The detection members of any onelayer can only be triggered one at a time (or not at all if the ballpasses perfectly through the gap); however, a second detection memberlayer can provide further information about misalignment errors. Forexample, if the ball 1705 is struck along path 1720, the ball will notcollide with any of the detection members 1715 a-d. As a furtherexample, if the ball 1705 is struck along path 1725, the ball withcollide with either 1715 a, or 1715 c, or both. If the ball 1705,traveling along path 1725, happens to pass through detection members1715 a and 1715 b without colliding with either detection member 1715 aor 1715 b, then the ball will still collide with detection member 1715c. Likewise, if the ball 1705, traveling along path 1730, happens topass through detection members 1715 a and 1715 b without colliding witheither detection member 1715 a or 1715 b, then the ball will stillcollide with detection member 1715 d.

While this invention has been particularly shown and described withreferences to example embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the scope of the inventionencompassed by the appended claims. While the above example embodimentsrelate to use in billiards, the disclosed devices and methods are not solimited and could be applied in other situations involving detectingdeviation of a ball, such as, for example, golf.

1. A device for detecting deviation of a ball from a path, the devicecomprising: a support structure; and detection members coupled to thesupport structure and arranged to allow the ball to travel between thedetection members, at least one of the detection members being movablerelative to the support structure and configured to move upon collisionwith the ball, movement of at least one of the detection membersindicating that the ball has deviated from a path of travel through thedetection members.
 2. A device as in claim 1 wherein the detectionmembers are rotatable about the support structure and configured torotate upon collision with the ball.
 3. A device as in claim 1 whereinthe support structure includes a substantially horizontal cross bar, andthe detection members are coupled to the cross bar and hang downwardfrom the cross bar.
 4. A device as in claim 3 wherein the detectionmembers swing freely with respect to the cross bar.
 5. A device as inclaim 3 wherein the detection members are configured to remain in adisplaced position after colliding with the ball.
 6. A device as inclaim 3 further including a center alignment guide coupled to the crossbar to assist with placement of the ball to travel between the detectionmembers.
 7. A device as in claim 2 wherein the rotational axes of thedetection members are substantially vertical.
 8. A device as in claim 1wherein the distance between the detection members is adjustable.
 9. Adevice as in claim 1 wherein a displacement of at least one of thedetection members indicates the direction of deviation of the ball fromthe path of travel between the detection members.
 10. A device as inclaim 1 wherein an amplitude of movement of at least one of thedetection members indicates a degree of deviation of the ball from thepath of travel between the detection members.
 11. A device as in claim 1wherein the deviation of the ball is caused by an implement striking theball to propel the ball and to induce spin on the ball.
 12. A device asin claim 11 further including a guide to assist the implement instriking the ball from a consistent angle.
 13. A device as in claim 11wherein the ball is a cue ball and the implement is a cue stick.
 14. Adevice for detecting deviation of a ball from a path, the devicecomprising: a support structure; and sensors coupled to the supportstructure and arranged to allow the ball to travel between the sensors,the sensors being configured to detect deviation of the ball from a pathof travel through the sensors.
 15. A device as in claim 14 wherein thesupport structure includes a substantially horizontal cross bar, and thesensors are coupled to the cross bar and aimed downward from the crossbar.
 16. A device as in claim 15 wherein the sensors include lasers. 17.A device as in claim 15 wherein the sensors include optical sensors. 18.A device as in claim 15 further including a center alignment guidecoupled to the cross bar to assist with placement of the ball to travelbetween the detection members.
 19. A device as in claim 14 wherein thedistance between the sensors is adjustable.
 20. A device as in claim 14wherein a triggering of one of the sensors indicates the direction ofdeviation of the ball from the path of travel between the sensors.
 21. Adevice as in claim 14 wherein the sensors are configured to measure adegree of deviation of the ball from the path of travel between thesensors.
 22. A device as in claim 14 wherein the deviation of the ballis caused by an implement striking the ball to propel the ball and toinduce spin on the ball.
 23. A device as in claim 22 further including aguide to assist the implement in striking the ball from a consistentangle.
 24. A device as in claim 22 wherein the ball is a cue ball andthe implement is a cue stick. 25-32. (canceled)
 33. A device fordetecting deviation of a ball from a path, the device comprising: asupport structure; and multiple sets of detection members coupled to thesupport structure and arranged to allow the ball to travel between thedetection members, each set of detection members including at least twodetection members, at least one detection member of each set beingmovable relative to the support structure and configured to move uponcollision with the ball, movement of at least one of the detectionmembers indicating that the ball has deviated from a path of travelthrough the detection members.